Ionic conduction in ammonium perchlorate doped with divalent ions

Abstract

D.c. electrical measurements are reported for sulphate-ion-doped and barium-ion-doped ammonium perchlorate. The extension of an impurity-dominated regime in sulphate-ion-doped ammonium perchlorate, and the fact that barium-ion-doped ammonium perchlorate displays no marked difference in electrical behaviour from that of the “pure” salt strongly suggests that the conduction process in ammonium perchlorate is controlled by interstitial ammonium ions. Measurements of surface conduction reveal no evidence for proton conduction at or near the surface where such a process would be expected to dominate via sublimation. The dominant point defect structure deduced from electrical measurements, i.e. interstitial NH⁺₄ ions would seem to favour electron transfer from ClO^–₄ to NH⁺₄ ions as the first step in the thermal decomposition of the solid, since this mechanism requires the existence of interstitial NH⁺₄ ions.